Rag Man

I bought a 98 Chevy Silverado has a plastic breather box on top of throttle body with VORTEC on it. Guy I bought it from said it was a 5.7 VORTEC however.... I spunt a rod bearing or two lol Anyway.. I pulled engine out to replace crankshaft and all the bearings ( rod and mains ) put it on my stand and look down to " GM LG 5.0 SGI " ?? both sides have the numbers 878 on heads on the right side back of block has numbers 10243878.. can anyone please help with just what I do have here ??